<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #bx_p {
            color: red
        }

        .c1 {
            color: blue
        }

        h1, #bx_p, .c1 {
            background-color: yellow
        }
        input[type="text"]{color: #666666}
        input[type="password"]{color:greenyellow}
    </style>
</head>
<body>
用户名:<input type="text" placeholder="用户名"><br>
密码:<input type="password" placeholder="密码">
<h1>这是h1</h1>
<p id="bx_p">冰箱</p>
<p class="c1">洗衣机</p>
<div>香蕉</div>
<div class="c1">苹果</div>
</body>
</html>